Matsuura Railway Nishi-Kyūshū Line

The line is the successor to a JR Kyushu local line that had been a designated deficit line, created on 1 April 1988 when the former Japanese National Railways / JR Kyushu Matsuura Line (松浦線) was converted to a third-sector railway. It is assembled from two originally separate railways built for mineral and ceramic traffic: an eastern half descended from the Imari Railway (later the JNR Imari Line) and a southern half descended from the Sasebo Light Railway (later the JNR Matsuura Line). The Japanese source notes that about half the route runs alongside National Route 204.

The eastern section began with the Imari Railway, which opened the Arita–Imari section to carry porcelain (陶磁器) on 7 August 1898 and merged into the Kyushu Railway that December. The Railway Nationalization Act of 1907 brought the Kyushu Railway into state hands, and under the 1909 designation of state-railway line names the Arita–Imari section became the Imari Line (伊万里線). The Imari Line was then extended in stages: to Imabuku (1930), Shisa — today Matsuura — (1933), Hiradoguchi, today Tabira-Hiradoguchi (1935), Senryū, today Senryūgataki (1939), and finally Hizen-Yoshii, today Yoshii (1944), where it met the Matsuura Line built from the south.

The southern section began with the Sasebo Light Railway, which opened a 762 mm (2 ft 6 in) gauge line from Ainoura via Ōno (present-day Hidariishi) to Yunoki on 27 March 1920 to carry coal (石炭); the English source dates the isolated Hidariishi–Ainoura coal line to the same day. Renamed the Sasebo Railway in 1923, the company expanded across the Kitamatsuura coalfield — reaching Saza by 1931 and acquiring the Kansai Coal Mining Company's line toward Sechibaru — and was nationalised in October 1936, when its lines were grouped as the Matsuura Line. A connection toward Sasebo opened in 1935.

Because the southern network was narrow-gauge and isolated, it was regauged from 762 mm to the national 1,067 mm gauge between 1943 and 1944, with realignments around Ainoura and a new 1,067 mm line between Kita-Sasebo and Hidariishi. A new alignment finally linking the two halves opened on 1 March 1945; the through Arita–Imari–Sasebo route then became the Matsuura Line, and the residual branches were split off as the Sechihara Line (世知原線), the Usunoura Line (臼ノ浦線) and the Yunoki Line (柚木線). Those branches were later closed — the Yunoki Line in 1967, the Sechihara and Usunoura lines in 1971 — and steam working ended on 15 March 1972 when 8620- and C11-class locomotives gave way to DE10 diesels. Freight ended on the Imari–Sasebo section in 1982 and on the Arita–Imari section in 1986.

The Matsuura Line was approved for abolition as a second-batch designated deficit line on 22 June 1984, and conversion was decided in March 1987. On 1 April 1987 it passed to JR Kyushu on the privatisation of JNR, and on 1 April 1988 it reopened as the Matsuura Railway Nishi-Kyūshū Line, with several stations renamed (Hiradoguchi became Tabira-Hiradoguchi the following year). Matsuura Railway then added many infill stations through the late 1980s and 1990s, bringing the total to 57. According to the Japanese source, the 200 m gap between Sasebo-Chūō and Naka-Sasebo is the shortest interval between adjacent stations on any Japanese railway line, tied with a pair on the Chikuhō Electric Railway. Services today are worked by single-car MR-400, MR-500 and MR-600 series diesel railcars, mostly one-person-operated locals, with a few morning rapid services between Saza and Sasebo; IC cards (nimoca) have been usable line-wide since 1 March 2020, and through running onto JR lines ended with the March 2020 timetable revision.

• 18987 August: the Imari Railway opens the Arita–Imari section (1,067 mm gauge) to carry porcelain; in December it merges into the Kyushu Railway.
• 19071 July: under the Railway Nationalization Act, the Kyushu Railway is nationalised and the route passes into state hands.
• 190912 October: with the designation of state-railway line names, the Arita–Imari section becomes the Imari Line.
• 192027 March: the Sasebo Light Railway opens a 762 mm-gauge light railway from Ainoura via Ōno (present-day Hidariishi) to Yunoki, built to carry coal.
• 1933The Imari Line is extended to Shisa (present-day Matsuura).
• 1935The Imari Line reaches Hiradoguchi (present-day Tabira-Hiradoguchi); the Sasebo Line's Sasebo–Kita-Sasebo connection opens.
• 1936October: the Sasebo Railway (formerly Sasebo Light Railway) is nationalised; its lines are grouped as the Matsuura Line.
• 193925 January: the Imari Line is extended to Senryū (present-day Senryūgataki).
• 194413 April: the Imari Line is extended to Hizen-Yoshii (present-day Yoshii), connecting with the Matsuura Line; regauging of the southern section is carried out 1943–1944.
• 19451 March: a new alignment linking the two sections opens; the through Arita–Imari–Sasebo route becomes the Matsuura Line, and the Sechihara, Usunoura and Yunoki branches are split off.
• 19671 September: the Yunoki Line branch (from Hidariishi) is closed.
• 197126 December: the Sechihara Line (from Yoshii) and the Usunoura Line (from Saza) branches are closed.
• 197215 March: steam locomotive operation ends as 8620- and C11-class engines are replaced by DE10 diesel locomotives.
• 198215 November: freight service on the Imari–Sasebo section is discontinued.
• 198422 June: the Matsuura Line is approved for abolition as a second-batch designated deficit line.
• 19871 April: on the privatisation of JNR the line passes to JR Kyushu; conversion to a third-sector railway had been decided in March.
• 19881 April: the line reopens as the Matsuura Railway Nishi-Kyūshū Line, with several stations renamed (Hiradoguchi becomes Tabira-Hiradoguchi the following year).
• 20201 March: the IC card nimoca becomes usable line-wide; through running onto JR lines ends with the March 2020 timetable revision.